After a long night of gambling (preferably in Las Vegas) you collect your winnings and cash out. You set those winnings aside, only to reach back in your pocket and use those winnings to play some more and hopefully aquire the same as you started with or more.
You win $300 on the roulette table on top of what you initially put in. You set it aside as your winnings. The next night, against your better judgement you use that $300 to keep on playing and you better leave with that original $300 or else you are a poor re-gambler.